This invention relates generally to improvements in a digital wristwatch which also functions as a computer to monitor operation of a bicycle, such as speed, distance traveled, and cadence (pedaling speed of the cyclist). More particularly, the invention relates to an improved dual mode circuit which temporarily converts a digital wristwatch into a bicycle computer.
Bicycle speedometers, odometers, and cadence counters are well-known which utilize sensors mounted with respect to the moving elements of the bicycle. Patents exemplary of such devices are seen in U.S. Pat. Nos. 4,156,190--Chittenden, 4,352,063--Jones, et al., 4,007,419--Jasmine, and 3,898,563--Erisman. Bicycle computers have been provided with microprocessor integrated circuits, with means for externally programming, setting, or changing the computations performed by the bicycle computer with push buttons or keyboards. Exemplary of such devices are U.S. Pat. No. 4,334,190--Sochaczevski, and 4,633,216, 4,636,769, and 4,642,606--all in the name of Tsuyama.
A number of patents have illustrated digital speed or distance measuring systems which may be calibrated or adjusted to allow for variations in wheel size, among these being the aforesaid Sochaczevski Pat No. 4,334,190, and 3,865,305--Sampey, and 3,614,617--Blake.
All of the aforesaid patents describe devices which are intended to only perform computations for the bicycle or other vehicle. While some of the aforesaid devices provide visual or aural indication of cadence, they do not provide the functions furnished by a modern digital wristwatch, such as time of day, day, date, elapsed time, chronograph, and so forth.
Digital wristwatches have been proposed, which also serve as calculators or computers to perform computations from an external keyboard, such as exemplary U.S. Pat. Nos. 3,955,355--Luce, 3,186,730--Yamamoto et. al., 3,803,834--Reese, and United Kingdom Patent Specification No. 1,349,044.
One such digital wristwatch has been proposed which receives external electrical signals, makes internal computations and displays the result of the computations on the normal timekeeping display in U.S. Pat. No. 4,022,014 issued May 10, 1977 to Lowdenslager and assigned to the applicant's assignee. This wristwatch has no provision for altering the type of computations or for changing the constants to be used in computations when the wristwatch is receiving external signals.
Accordingly, one object of the present invention is to provide an improved dual mode circuit for a bicycle watch.
Another object of the invention is to provide an improved circuit for keeping time in a "watch mode" and for receiving external signals and making computations in a "bike mode" and displaying the computations.
Another object of the invention is to provide an improved bicycle watch with means for altering the type of computations and changing the constants to be used in a "calibration mode.